Spheroidal gel particles



Filed April 19, 1944 Patented' Sept. 18, 1945 sPHEnomAL GEL rAaTloLEsvMilam M. Marisa, Woodbury, N. J., assigner to Socony-Vacuum OilCompany, Incorporated, a

corporation of New York Application April 19, 1944, Serial No. 531,814

9 Claims.

This invention relates to spheroidal bodies of inorganic oxide gelscontaining masses foreign to the gel structure. This application is acontinuation in part of my prior copending application Serial No.491,544, filed June 19, 1943.

My said prior application describes a process for forming compositehydrogel spheroids by incorporation with a gela-'ble sol of pulverizeddried gels and other matter foreign to said sol. 'I'he sol is theninjected into a body of water immiscinble liquid wherein the solseparates into a plurality of globules which set to firm hydrogelspheroids in the liquid. Primarily, the said prior case is directed toformation of globules having a core of foreign matter surrounded by ashell of hydrogel. In addition, it is disclosed in said application thata foreign body may be included in the nished hydrogel by suspending itin one of the reactant solutions used to form the gelable sol or in thesol before gelation occurs. 'Ihis latter concept is the basis of thepresent application.

Prior to the work of the present applicant, dried porous inorganicoxides for use as catalysts, adsorbents and the like, includingpartially dried bodies used for zeolytic base exchange in 'waterpurification, had been prepared according to one of three well definedmethods. The Patrick process involves addition of a-solution, such aswater giass, to acid to produce a sol which sets to a rm hydrogel in aperiod of several hours. These gels are prepared at high acidity, moreacid than pH 1. Porous bodies are also prepared by precipitation byadding acid to such solutions as water glass or water glass containingan aluminum salt. 'Ihe precipitate is soft and readily separated byfiltration'from the aqueous liquor. A third process involves'mixingsolutions in such manner that gelatinous precipitates are formed andincluded in a gel which sets up immediately upon reaching a certainvalue of vconcentration and pH. These methods are not suited toformation of smooth surfaced spheroidal particles .by injection' of solto a body of water immiscible liquid. The gela- I tion time of thePatrick gelsv is'too long, gelatinousA precipitates will not formglobules and the mixed precipitate and gel sets up immediately, givingno time for globule formation. i

I have now perfected a method which, in some of its embodiments, issimilar to mixed gel and precipitate formation in that bodies foreign to1 the gel are included in the gel structure as occlusions. Bythismethod, I am able to prepare a wide variety of composite bodies havingthe characteristic smooth hard surfaces and spheroidal liquid. Theforeign substances included in the gel globules may serve a number ofpurposes. In catalytic gels, the added substance may be a catalystmodifier or may itself be catalytic, such as finely divided metals,oxides, suldes, etc. The 4 added substance may be added for its thermaleffect, thus inert bodies of high specific heat may be added to crackingcatalysts to aid in temperature control on regeneration. Metals, quartz,alundum, glasses, etc., may be used for this purpose. Where the gel isto be used for zeolytic water softening, a different type of baseexchange material may be occluded; for example an anion exchangingresin'may be incorporated in a cation exchanging silica-alumina gel.

The added substance may be utilized to modify porosity and otherphysical characteristics. Liquids, gases and combustible solids may thusbe added to cause large pores to occur in the finished spheroids afterdrying, burning or other suitable treat-ment. A more highly porous orless porous substance such as a precipitate or gel of different porositymay be occluded. The dispersion of gases in the sol is described in mycopending application Serial No. 461,454, filed October 9, 1942.

These objects and advantages of the invention are obtained by eiectingdispersion in a gelable sol of particles ixnmiscible with the sol,injecting the sol to a body of a liquid immiscible therewith andretaining the so formed globules of sol in the liquid until gelationtakes place. Thereafter the hydrogel spheroids are removed from theliquid and treated, as by washing and drying, to yield the desiredproduct. Other objects and advantages of the invention will appear fromconsideration of preferred embodiments of the invention discussed belowin connection with the annexed "drawings, wherein:

Figure 1 is a diagrammatic representation of '5 apparatus for practicingthe invention, and

Figure 2 isa. modified type of apparatus for mixing a separate' phasewith pre-formed gelable sol.

Referring specifically to Figure 1,a gel in 'spheroidal form may beprepared with dispersion or' apowdered solid therein by adding the solidto` one of the reactant solutions mixed to forma gelable sol. Forpurposes of iilustratiomFigure 1 may be considered in connection withpreparation of a silica-alumina cracking catalyst in spneroidal formcontaining a dried Iandpowdered silica-alumina gel of the same ordifferent nature.

shape of gels formed asglobules in an immiscible Two solutions are mixedtogether to prepare a. sol in this process. One ofthe solutions is adilute water glass and the other is acid. A Water tion in the agitator.

soluble aluminum compound is incorporated in one or both of these twosolutions, e. g., aluminum sulfate in the acid or sodium aluminate inthe water glass. To one of these solutions, a nely divided, preferablypowdered, dried silica-alumina gel is added. Preferably, the powdereddry gel is added to the water glass; since the acid solution tends todissolve alumina and will thus affect the dry gel in a manner which isdisadvantageous for some purposes.

In the apparatus of Figure 1, water glass and acid solutions aresupplied in predetermined relative amounts by pipes I and H and meteringpumps I2 and I3, respectively. A powdered dry silica-alumina gel fromhopper I4 is supplied to line I2 by worm feed I6 driven by motor I6.Usually, worm feed I5 will -be so operated as to supply the powdered gelat a predtermined constant rate. The mixture of powdered gel and waterglass is then passed through a disperslng device, such as bailledchamber I1 in order to disperse the powdered gel uniformly through thewater glass solution.

The dispersion of powdered gel in water glass is then efficiently mixedwith acid solution in mixing nozzle,I8 and injected into the top of aforming tower I9 containing a liquid immiscible with water, for example,a light petroleum distillate. As indicated at 20, the level of the oilis generally above the nozzle opening. In the oil, the sol separatesinto spheroidal globules which fall through the oil and set to a firmhydrogel before passing through an interface 2| into a layer of waterbelow the oil. The gel spheroids then are picked up by a stream'of waterin a chamber 22, supplied by pipe 23, and carried in said stream througha goose-neck 24 which is vented to the atmosphere through vent 25 at alevel to maintain level 20 of the liquid in forming tower I9.

Alternatively, the gelable sol may be made up and the foreign bodydispersed therein before injection to the oil column. The apparatus ofFigure 2 is particularly adapted to practice of that embodiment of theinvention. A sol having a suitable gelation time is supplied by pipe 26from a source, not shown, which may be identical with mixing nozzle I8except that a pipe is connected to the discharge opening. The sol ispassed to an agitator 21 where it is thoroughly mixed with a separatephase which may be introduced to line 26 by a worm feed as in Figure 1.A series of xed vanes and rotatable vanes, carried by driven shaft 28,efllciently mix the sol with the added material in agitator 21 and themixture is then injected below the level 20 of an oil column in chamberi9.

This type of dispersion is very satisfactory for introduction of aliquid or gaseous material to the sol. Fluids may be supplied underpressure to a hollow shaft 28 to be injected through openings in theshaftl and/or the vanes mounted thereon.

When dispersing a separate phase into la. preformed sol, it is advisableto use a sol having a relatively long gelation time to avoid gel forma-This does not necessarily mean that the oil column must beproportionately deep since the gelation time decreases with increasingtemperature and the sol may be introduced to an oil column of elevatedtemperature whereby it is heated and caused to gel in a relatively shorttime. A heating coil 29 is shown in chamber I9 of Figure 2 for thatpurpose. If a concentrated gel is desired, the reacting solution may becooled to Vnear freezing temperatures and maintained at that level untilinjected to the oil, which may in that case be at room temperature, ifdesired.

The nature of the process is further illustrated by specific examplesgiven below, it being understood that the nature of the foreign matterin-` troduced according to any of the examples may be varied within thescope of the invention as discussed generally above.

Example 1 A solution of sodium silicate con-taining 105 grams of SiOzper liter was prepared by diluting N" brand of sodium silicate (28.7%SiOz, 8.9% NazO). This solution was passed through an agltating devicewith 200 grams per liter of mesh dried silica alumina gel prepared bycrushing the product of previous similar process in which a foreignmaterial was not added. Thereafter the dispersion was mixed with asecond solution containing 34.10 grams of AMSOQ: and 25.05 grams ofH2504 per liter at the ratio of 1.00 volume of the former solution to0.780

volume of the latter. IIfhe resulting colloidal solution leaving themixer through orifices was introduced into the top of a column of gasoil whose depth was eight feet. The globules of solution fell throughthe oil and gelled before passing into the layer of water locatedbeneath the oil. The gel in the globular form was conducted out of thebottom of the column in a stream of water and on removal from the water,it was washed with petroleum naphtha to remove oil from its surface. Itwas then washed with water and NHACl solution to replacezeoliticallyheld sodium ions by ammonium ions which are capable of beingdriven off as NH3 gas by heat. The gel was dried slowly and uniformly atF. until shrinkage was substantially complete and the drying wascontinued at a gradually increasing temperature up to 1050 F. at whichtemperature it was maintained for two hours. The silica-alumina gelretained its spheroidal shape during the washing and drying operations.

The time of gelation for the concentration and proportions of reactantsgiven above was about ten seconds, while the pH was 6.9. The gas oilemployed was a fraction of Oklahoma City Gas Oil having a boiling rangeof 471 to 708 F.' and a specic gravity of 0.846.

Example 2 Example 3 A solid cracking catalyst was made according to thekprocess of Example 2 except that the air was injected directly into themixing nozzle. A product essentially the same as that of Example 2 wasproduced.

Example 4 This example illustrates the effect of cooling the solutionsmixed to form the gelable sol and mixing a foreign phase with the solbefore injecting to the forming column. The silicate solution and acidof Example 1 were cooled to 40 F. and efficiently mixed. At thistemperature,

the sol had a gelation time greater than one hour.A

The sol was then passed Vto an'agitator (Figure 2) wherein one volume oigas oilwas efficiently dis-` of oil maintained at about 80". F.resulting in formation of composite spheroids of about A10 mm. averagediameter each containing a plu-`V rality of occluded oil droplets. (Itis noted that a gas or liquid dispersed in a gelable sol shows sometendency to move to a globule surface and be lost. In some cases slightdispersions remain in the surface of the spheroidal hydrogel particles.)The hydrogel of `this example was washed and dried as above and thencontacted with air at about 1050 F. to burn out residual carbonaceousmaterial leaving a product very similar to that of Example 2.

All the products described above were found to be excellent catalystsfor cracking of hydrocarbon oils and to have excellent characteristicsthereafter removing thev globules of hydrogel so l-ior med;ysaid smxa,ll'axnountsV of said gas being of suchsize and quantity that the majorproporj tion of said hydrogel globules will include a plurality of'saidparticles of said gas.

'A process formalring spheroidal particles of inorganic oxidegels-modified vby inclusion of substances forming discontinuities in thegel mass 'which comprises preparing a gelable aqueous sol forregeneration by burning.

- I claim:

1. A process for makingspheroidal particles of f inorganic .oxide gels.modified by inclusion of substances forming discontinuities in the gelmass of'a gas insolublein said sol whereby thesaid gas is dispersedthrough the sol as particles of a phase discontinuous with'the sol,injecting-said sol containing said dispersed gas into a body of awaterimmiscible liquid whereby the sol is caused to take the form of aplurality of separate substantially spheroidal globules, retaining saidglobules in said liquid until gelation of said sol has occurred andthereafter removing the globules of hydrogel so formed; said smallamounts of said gas being of such size and quantity that the majorproportion of said hydrogel globules will include a plurality of saidparticles of said gas.

2. A process for making spheroidal particles of silica containing gelsmodified by Ainclusion of substances forming discontinuities in the gelmass which comprises preparing a gelable aqueous sol containing silica,eiecting dispersion in said sol of small amounts of a gas insoluble insaid sol whereby the said gas is dispersed through the sol as particlesof a phase discontinuous with the sol, injecting said sol containingsaid dispersed gas into a body of a Water-immiscible liquid whereby thesol is caused to take the form of a plurality of tity that the majorproportion ,of said hydrogel globules will include a pluralitylof s aidparticles Y ofsaidgas. e K l. y 3. A process for makingspheroidalfparticles ofv I silica `alumina gels modified byinclusionE-ofsubey i stances: forming discontinuities inthe gelmass which'comprisespreparing a gelable aqueous sol containingsilca andffalumina, effectingdispersion 'l of at least one water insoluble inorganic oxide, eilectingdispersion in said sol of small amounts o'f a gas insoluble in said solwhereby the said gas is dispersed through the sol as particles of aphasefdiscontinuous with the sol, injecting said sol containing saiddispersed gas into a body of a Water immiscible liquid whereby the solis caused to take the form of a plurality of separate substantiallyspheroidal globules, retaining said globules in said liquid untilgelation of said sol has occurred removing the globules of hydrogel soformed, washing said globules and drying the washed globules; said smallamounts of said gas being of such size and quantity that the majorproportion of said hydrogel globules will include a plurality of saidparticles of said gas.

g 5. A process for'making spheroidal particles of silica containing gelsmodified by inclusion of substances forming discontinuities in the gelmass which comprises preparing a gelableaqueous sol as particles of aphase discontinuous with the sol,

`injecting said sol containing `said dispersed gas in said sol of smallamountslof av gas insoluble in` ,y

said sol whereby' the 'said gas is' dispersed through y the sol asparticles of aphase discontinuous iirithk the sol, injecting said sl`containing said',A dispersed gas into a body of a water immisciblerliq?` uid whereby the sol ,is caused to take the form of a pluralityofseparate substantially' sphe-4 roidal globules, retaining saidyglobules in said liqd uid until gelation of said sol has occurred andinto a body of a water immiscible liquid whereby the sol is caused totake the form of a plurality of separate substantially spheroidalglobules, retaining said globules in said liquid until gelation of saidsol has occurred, removing the globules of hydrogel so formed, washingsaid globules and drying the washed globules; said small amounts of saidgas being of such size and quantity that the major proportion of saidhydrogel globules will include a plurality of said particles of saidgas.

6. A process for making spheroidal particles of silica alumina gelsmodified by inclusion of substances forming discontinuities in the gelmass which comprises preparing a gelable aqueous sol containing silicaand alumina, eiectng dispersion in said sol of lsmall amounts of a gasinsoluble in said sol whereby the said gas is dispersed through the solas particles of a phase discontinuous with the sol, injecting said solcontaining said dispersed gas into a body of a water immiscible liquidwhereby the sol is caused to take the form of aplurality of separatesubstantially spheroidal globules, retaining said globules in saidliquid until gelation of said sol has occurred, removing the globules ofhydrogel so formed, washing said globules and drying the washedglobules: said small f t amounts'.of'said` gas being of such sizevandquantitythat the major proportionvof saidhydrogel globules will includeva plurality of saidparticles loisaid gas.- y

' inorganicoxidey gels modifiedby inclusion of sube M7.' Afzprocess formaking spheroidal particles'of stancesforming discontinuities in theVgel mass `[which comprises preparing a gelable aqueous sol `ofat least`one Water insoluble inorganic oxide, feecting. dispersion in saidsol-of small amounts y of air wherebythefainis dispersed through the`.l.-s,ol aslparticles of a' phasediscontinuous with the v's ol,injecting saidsol containing said dispersed air into albody oi `a waterimmiscible liquid y whereby the sol-iscaused to take the formof aplurality oi separate substantially spheroidal globules, retaining saidglobules in said liquid until gelation of said sol has occurred,removing the globules of hydrogel so formed. washing said globules anddrying the washed globules: said small amounts of said air being of suchsize and quantity that the major proportion of said hydrogel globuleswill include a plurality of said particles of air.

8. A process for making spheroidal particles of silica containing gelsmodified by inclusion of substances forming discontinuities in the gelmass which comprises preparing a gelable aqueous sol containing silica.eiecting dispersion in said sol of small amounts of air whereby the airis dispersed through the sol as particles oi a phase discontinuous withthe sol, injecting said I sol containing said dispersed air into a bodyof so formed, washing said globules and drying the washed globules; saidsmall amounts oi said air being of such size and quantity that the maiorproportion of said nvdrogel globules will include a plurality of saidparticles of air.

9. A process for making spheroidal particles of silica alumina gelsmodied by inclusion of substances torming discontinuities inthe gel masswhich comprises preparing a gelable aqueous sol containing silica andalu-mina, eii'ecting dispersion in said sol o! small amounts of airwhereby the air is dispersed through the sol as particles of a phasediscontinuous with the sol, injecting -said sol containing saiddispersed air into a `body of a water immiscible liquid whereby the solis caused to take the form of a plurality of separate substantiallyspheroidal globules. retaining said globules in said liquid untilgelation of said sol has occurred, removing the globules of hydrogel soformed, washing said globules and drying the washed globules; said smallamounts of said air being of such size and quantity that the majorproportion of said hydrogel globules will include a plurality of saidparticles of air. l

MILTON M. MARISIC.

